1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to a device for the treatment of pulmonary arterial hypertension.
Pulmonary arterial hypertension is a disease that affects a large number of people, either directly through pulmonary fibrosis or indirectly as a result of respiratory failure or left ventricular failure. Pulmonary arterial hypertension usually results from an increase in peripheral pulmonary vascular resistance and a decrease in pulmonary arterial compliance.
One approach for treating pulmonary hypertension relies on placing a balloon in the trunk of the pulmonary artery, or two balloons in the branches of the pulmonary artery bifurcation. The balloon(s) are connected to an implantable port and are normally inflated with a gas to partially extend across the trunk or the branches. The port will hold excess gas that provides a “gas reserve.” The balloon(s) are fully expanded during right ventricular diastole, and thus will limit the backflow of blood. During right ventricular systole, however, the balloons compress in response to the increased blood pressure so that they do no significantly impede the flow of blood into the pulmonary artery. Such compression temporarily generates an overpressure which is mitigated by the excess volume provided by the implantable port as well as by the conduit connecting the port to the balloon.
While quite effective for treating pulmonary hypertension, the placement of these balloons in the trunk or the branches of the pulmonary artery can be difficult. In particular, with present balloon designs and placement protocols, the balloons may become displaced during systole or diastole, and such displacement can reduce device efficiency and in some cases cause vascular trauma. Moreover, the present devices can be difficult to remove and replace if they become leak or otherwise become dysfunctional over time.
For these reasons, it would be desirable to provide improved pulmonary artery balloon catheter designs and placement protocols which minimize the risks associated with balloon mobility. The balloon designs should also be amenable to replacement should that become necessary. The present invention will meet at least some of these objectives.
2. Description of the Background Art
Pulmonary arterial catheters and other devices are described in U.S. Pat. Nos. 4,902,273; 6,017,324; 6,053,891; and 8,876,850; and PCT Applications WO1993/17731 and 2013/185138.